WebView on Android should save the session with logged in user?

I have an application that only loads a website. The login works normal, but it happens after a few hours the session disappears. I talked to the site owner about increasing the cookie expiration time, he said that he had already done so and that the login was in the session, not the cookies. Researching this (not my area), so I understood the difference between them is that the cookie gets saved in the browser and the session gets lost when it is closed. I have already tried setAcceptCookie and setAcceptThirdPartyCookies , CookieSyncManager , save cookies with SharedPreferences and load them in webview with setCookie in onCreate , but nothing has changed. That's where my question is, is the problem really on the application side? If login is being lost, would not it be because of the nature of the session? I saw that Google made changes related to webview in api 21, could that be the cause too?